Electrical plug connectors and sockets therefor



WITNESS June 14, 1955 R. HAPPE ETAL 2,710,949

ELECTRICAL PLUG CONNECTORS AND SOCKETS THEREFOR I Filed Sept. 10, 1952 a I), v

,, 7 7 mun... liiis INVENTORS. CZqynoZd Fflyope and BY iyred adau ille ATTORNEY United States Patent ELECTRICAL PLUG CONNECTORS AND SOCKETS THEREFOR Reynold Happe, Pittstown, and Wilfred O. Langille, Chester, N. J., assignors to The Singer Manufacturing Company, Elizabeth, N. J., a corporation of New Jersey Application September 10, 1952, Serial No. 308,798

2 Claims. (Cl. 339-258) This invention relates to electrical plug connectors adapted, more particularly, for use with motor-driven family sewing machines,

An object of the invention is to provide a plug connector having improved casing and contact elements which are readily manufactured and assembled.

Another object of the invention is to provide a socket element for a plug connector, which socket element may be readily manufactured from a single sheet of metal and which is so designed that when it is assembled in the plug connector it will automatically be locked in its proper position. a

With the above and other objects in view, as'will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

in the accompanying drawings,

Fig. 1 represents a perspective view of the motor bracket of an electric sewing machine and carrying a connector of which the plug member embodies the invention.

Fig. 2 represents a perspective view of a connector socket member shown in Fig. l and which is adaptedto receive a plug member embodying the invention.

Fig. 3 represents a central transverse section taken through the connector socket member.

Fig. 4 represents a perspective view of the plug member complete.

Fig. 5 represents an exploded perspective view of the two halves of the plug member.

Fig. 6 represents a central transverse section through the assembled plug member.

Fig. 7 represents a plan view of a sheet metal blank from which a socket connection is formed.

Fig. 8 represents a perspective view of a complete socket member with an electrical wire connector attached thereto.

Referring now to the drawings, 10 represents a cast motor-supporting bracket of a sewing machine, of the type represented in U. S. Patent No. 1,488,234, March 25, 1924. The bracket 10 has a slotted foot portion 11 which is adapted to be bolted to the sewing machine bracket-arm standard, and an angle portion 12 which is adapted to carry the sewing machine driving motor. The bracket 10 is also formed with a seat 13 to which a socket member 15 is secured by a screw 14.

The socket member 15 comprises a casing of molded insulation material, preferably Bakelite, having a plugreceiving cavity 16 in the bottom end wall 17 which is provided with a plurality of apertures 18 for snugly receiving therein a plurality of terminal pins 19, 19. The outwardly extending end portions of the terminal pins 19 are threaded as at 20 for receiving thereon binding post nuts 21. The binding post nuts are adapted to se- 2 cure toa respective one of the terminal posts an appropriate lead wire for a sewing machine light, motor and motor controller.

There may be fastened under the head of the screw 14 a ground contact blade 22 which is in metallic connection with thebracket 10 and hence with the frame of the sewing machine to which the bracket 10 is bolted.

The plug member to be inserted in the cavity 16 of the socket member 15 comprises a hollow casing gen- 27 in which may be disposed the bent end portion of a spring contact blade 28 the shank 29 of whichis heldby a headed-over end of a bolt 30 which functions in conjunction with bolts 31 to secure the two halves of the plug together in a manner which will be hereinafter set forth infurther detail. The member 29 is provided with a binding screw 32 for a ground conductor 33. Thus, the plug casing 23 is made of two molded separable sections 34 and 35 of Bakelite held together by screws 30 and 31 and nuts 36.

The plug section 35 is preferably formed internally with a lengthwise extending cavity 38 which isadapted to register with a similarly disposed cavity 39 formed in the plug section 34. It is to be particularlynoted that the opposite end portions of the cavities 38 and 39 are formed as conduit-receiving seats generally designated by the numeral, 40. e As may be particularly noted in Fig. 4, wheneverv the plug casing halves 34 and 35 are in the assembled position, the registeringseats 49 will grip conductor cord insulation elements 41 and 42 in a conventionalmanner. In Fig. 5 it will be observed that the plugcasings 34 and 35 are provided with a plurality of through apertures 43, 43 which receive the above noted securing screws 30 and 31. v v I 7 Referring particularly to Figs. 5 and 6, it is to be understood that each of the plug casings 34 and 35 is provided with three semicircular grooves 44. of vhich each leads directly from its associated cavity 38 or 39 to the outside of the plug casing half. The semicylindrical grooves are so disposed that whenever the plug casing halves are assembled together in a manner as disclosed in Figs. 4 and 6 they will register together in pairs so as form the pin-receiving apertures 25 illustrated in Fig. 4.

The plug casing half 34 differs from its associated half 35 in that each of the grooves 44 thereof is provided intermediate its groove wall with a small recess 45 illustrated in Fig. 6. The purpose of the recesses 45 will be hereinafter set forth.

Referring particularly to Figs. 1, 4 and 5, the plug connector 23 is adapted to receive a three-wire cord conductor 46 and a two-wire cord conductor 47 the end portions of which are respectively covered by means of the above noted cord conductor insulator sleeves 41 and 42. The wires of the conduits 46 and 47 are adapted to energizea light fixture, a motor and a motor controller of a sewing machine outfit in a manner as is best set forth in U. S. Patent No. 2,249,619, July 15, 1941, and, thus, no further explanation of this particular type of wiring is deemed necessary for the present purposes. The plug 23 is adapted to house three terminal-pin receiving sockets each designated generally by the numeral 48 which all face in the same direction within the openings 25 so as to be engaged by the terminal pins 19, 19 when the plug 23 is inserted into the socket cavity 16.

More especially, each of the sockets 48 is adapted to be formed from a piece of sheet metal material which is best illustrated in Fig. 7. This sheet metal blank generally comprises a pair of laterally spaced rectangular parallel strips 49 and 50 connected together intermediate their ends by a relatively narrow bridge piece 51. The opposite end portions of the strip 49 are formed with reduced lips 52, 52 of which the purpose will be hereinafter described. In forming the socket from the blank, the strip 49 is folded so as to form a longitudinally split cylindrical terminal-receiving tube 53 having its meeting edges each provided medianly of its length with a lip 52; these lips together forming a radially outwardly extending tang 54. Also, the strip 50 is bent so as to form a wire-clamping member having a pair of flatwise opposed clamp plates 55, 55 both integrally connected with one end of the tube 53 by means of the segmental bridge piece 51. The clamping plates are provided with a pair of aligned apertures 56, 57 of which the latter is threaded so as to receive a clamping screw 58. The clamp plate carrying the threaded aperture 57 is provided with a flange 59 which overlies the free end of the other clamp plate so as to form an abutment for confining a wire 60 between the screw 58 and the flange 59.

Referring particularly to Figs. 5 and 6, it is to be understood that the housing 23 is adapted to receive three sockets 48, with each socket being disposed within a respective one of the plug apertures 25, 25 in a manner such that each of the tangs 54 will be disposed within a respective one of the recesses 45 so as to lock the split cylindrical tube 53 in a manner such that the tube cannot shift axially within the seat 25. It is also to be noted that the clamping plates '55, 55 of each socket 48 will be disposed within the housing cavity 39 so that the socket may be conveniently connected to one of the wires carried by the respective one of the conduits 46 or 47.

From the above, it will be appreciated that when the two halves 34 and 35 of the plug member 23 are fastened together by means of the bolts 30 and 31, the live sockets 48, 48 are disposed entirely Within the plug member and are completely covered and cannot be touched by anyone. Furthermore, it is pertinent to note that each of the sockets 48 is snugly mounted within the registering semicircular grooves 44, 44 of the two housing halves and that the tang 54 of each of the sockets is disposed within a respective one of the recesses 45 provided in the housing half 34 so as to prevent either the rotation of the socket about its tube axis or the shifting of such tube lengthwise of its axis. Those skilled in the art will readily appreciate that the housing halves 34 and 35 are designed so as to facilitate their manufacture by a conventional plastic moulding process while at the same time the sockets 48, 48 are designed in a manner such that they may be efliciently and inexpensively manufactured from unitary sheet metal blanks.

Having thus set forth the nature of the invention, What We claim herein is:

l. A socket for a plug connection comprising a 1ongitudinally split cylindrical terminal-receiving tube having the meeting edges each provided medianly of the length of the tube with a lip, said lips together forming a radially outwardly extending tang, said tube having at one end a U-shaped wire-clamping member having the base of the U secured to said tube and having the legs of said U comprising flatwise opposed clamp-plates each substantially coplanar with a lip of said tang, one of said clamp-plates having a flange overlying the free end of the other clamp-plate, said clamp-plates being provided with a pair of aligned apertures of which one is threaded, and a screw disposed Within said apertures for securing said clamp-plates in wire-clamping relation.

2. A socket for a plug connection comprising a pair of laterally spaced rectangular parallel strips of sheet metal connected together intermediate their ends by a relatively narrow bridge piece, one of said strips having its two opposite end portions each provided with an outwardly extending lip narrower in width than the strip itself and with such strip being bent to form a longitudinally split cylindrical tube for receiving therein a terminal pin and with said two lips together forming a radially outwardly extending tang, the other of said strips being bent to form a pair of parallel flatwise opposed clampplates for receiving a wire therebetween, said clampplates being provided with a pair of aligned apertures, and a clamping screw disposed within said apertures.

References Cited in the file of this patent UNITED STATES PATENTS 1,417,452 Catlin May 23, 1922 2,074,957 Chirelstein Mar. 23, 1937 2,085,707 Shore June 29, 1937 2,451,800 Buchanan Oct. 19, 1947 

